1. Field of the Invention
The present invention relates to a cooling apparatus boiling and condensing refrigerant that cools a heat-generating member by boiling heat transfer to a refrigerant.
2. Description of the Related Art
Presently there is a marked trend toward a higher density of heat generation and a higher temperature of heat flux in CPU chips for personal computers, devices for inverters, etc. that control large currents in vehicles, etc. due to the improvement of their performances. On the other hand, a cooling apparatus, which uses a boiling and condensing refrigerant, is suited to cool a heat-generating member that has a high density of heat generation because it can effectively remove heat from the heat-generating member by utilizing phenomena, of boiling and condensating a refrigerant, that has a high heat transfer rate.
The structure, however, of a cooling apparatus boiling and condensing refrigerant needs to be improved in order to cover an area where the density of heat generation of a heat-generating member exceeds 50 W/cm2. In relation to this, it is widely known to prevent devices from being excessively heated by designing a tunnel structure in which a space that includes a boiling surface communicates with an outside space via communication openings whose opening area is small, and by providing a thin liquid film on the boiling surface.
In Japanese Unexamined Patent Publication (Kokai) No. 2001-116474, a cooling apparatus boiling and condensing refrigerant in which the above-mentioned tunnel structure is applied to a refrigerant tank has been disclosed. The refrigerant tank mentioned above, however, is formed of extruded materials, therefore, there are difficulties in manufacturing it actually. Moreover, even if such a tunnel structure can be realized, it has disadvantage in costs because of the necessity of cutting work.
The present invention has been developed with the above-mentioned circumstances taken into account and the objective is to provide a cooling apparatus boiling and condensing refrigerant that can realize high performance in a boiling section using a low-cost means.
The First Aspect of the Apparatus of the Present Invention
The cooling apparatus boiling and condensing refrigerant of the present invention comprises a refrigerant container that has a structure in which plural intermediate plates are stacked and both sides of the stacked intermediate plates, in the direction of stacking, are stacked by external plates, respectively.
The intermediate plates used in the refrigerant container include a first intermediate plate and a second intermediate plate that are stacked sequentially upon the external plate, and if the openings of the first intermediate plate are referred to as first openings and the openings of the second intermediate plate are referred to as second openings, then the first openings and the second openings communicate with each other and the opening dimension of the communicating sections is smaller than that of the first openings.
In this structure, it is possible to easily realize a tunnel structure only by designing the opening dimension or opening position of the first openings provided in the first intermediate plate and that of the second openings provided in the second intermediate plate.
The second aspect of the apparatus of the present invention
In the first aspect of the cooling apparatus boiling and condensing refrigerant, both the first openings and the second openings are formed into an elongate slit-shape, and provided so that the width of the slits of the first openings is wider than that of the second openings.
In this way, it is possible to make the opening dimension of the communicating sections, through which the first openings and the second openings communicate with each other, smaller than that of the first openings, and to realize a tunnel structure.
The third aspect of the apparatus of the present invention
In the first aspect of the cooling apparatus boiling and condensing refrigerant, the shapes of the first opening and the second opening are substantially similar to each other and the opening dimension of the first openings is larger than that of the second openings.
The first opening and the second opening may be formed, for example, into an elongate slit-shape as described in the second aspect of the apparatus of the present invention, but it is not necessary in particular to limit the opening shapes and they may be formed into circles, polygons, or the like. When, however, the opening shape is circular, polygonal or the like, it is possible to make without fail the opening dimension of the first openings larger than that of the second openings by designing the opening shapes so that they are substantially similar to each other.
The fourth aspect of the apparatus of the present invention
In the first aspect of the cooling apparatus boiling and condensing refrigerant, parts of the second openings communicate with the first openings so that the opening dimension of the communicating sections, through which the first openings and the second openings communicate with each other, has a fixed value.
In this structure, regardless of the opening dimension of the second opening, the opening dimension of the communicating sections can be kept to the fixed value because the parts of the second openings communicate with the first openings. In this case, as it is not necessary to strictly manage the opening dimension of the second openings, the second openings can be formed, for example, by press working. In other words, it is possible to form the openings in the communicating sections so that its dimension is further smaller without depending on the quality of the press molding of the second openings.
The fifth aspect of the Apparatus of the present invention
At least two second openings communicate with one of the first openings, in the first aspect of the cooling apparatus boiling and condensing refrigerant.
In this case, it is possible to form a tunnel structure the tunnel portion of which is long and achieve high performance in the boiling section at a low cost because at least two communicating sections, through which the second openings communicate with the first opening, are provided.
The sixth aspect of the apparatus of the present invention
The cooling apparatus boiling and condensing refrigerant of the present invention comprises a refrigerant container that has a structure in which plural intermediate plates are stacked and both sides of the stacked intermediate plates, in the direction of stacking, are stacked by external plates, respectively.
The intermediate plates used in the refrigerant container include a first intermediate plate and a second intermediate plate that are stacked sequentially upon the external plate, and if the openings of the first intermediate plate are referred to as first openings and the openings of the second intermediate plate are referred to as second openings, the first openings and the second openings communicate with each other and the opening dimension of the communicating sections is smaller than that of the first openings. Moreover, the first intermediate plate has communication paths through which the plural first openings communicate with each other.
In this structure, it is possible to easily realize a tunnel structure only by designing the opening dimension or opening position of the first openings provided in the first intermediate plate and that of the second openings provided in the second intermediate plate.
Moreover, as the plural communication paths through which the plural first openings communicate with each other (for example, one of the first openings and another one of the first openings) are provided in the first intermediate plate, even when evaporated bubbles pass continuously from one of the first openings through the communicating sections (communicating sections between the first openings and the second openings), a liquid refrigerant can enter the one of the first openings from the other one of the first openings via the communication path. In this way, it is possible to prevent the liquid refrigerant from being exhausted within the first openings and a sufficient cooling performance can be maintained.
The seventh aspect of the apparatus of the present invention
The communication path provided in the first intermediate plate enables the communication between a first opening (one of the first openings) within which a refrigerant is in a state of boiling and another first opening (another one of the first openings) within which a refrigerant is not in a state of boiling, in the sixth aspect of the cooling apparatus boiling and condensing refrigerant.
In this case, as a liquid refrigerant is supplied to the one of the first openings from the other first opening via the communication path, the liquid refrigerant can be prevented from being exhausted in the one of the first openings within which the refrigerant is in a state of boiling.
The eighth aspect of the apparatus of the present invention
The cooling apparatus boiling and condensing refrigerant of the present invention comprises a refrigerant container that has a structure in which plural intermediate plates are stacked and both sides of the stacked intermediate plate, in the direction of stacking, are stacked by external plates, respectively.
The intermediate plates used in the refrigerant container include a third intermediate plate, a first intermediate plate and a second intermediate plate that are stacked sequentially upon the external plate, and if the openings provided in the first intermediate plate are referred to as first openings, the openings provided in the second intermediate plate are referred to as second openings, and the openings provided in the third intermediate plate are referred to as third openings, then the first openings and the second openings communicate with each other and the opening dimension of the communicating sections is smaller than that of the first openings. Moreover, the third openings are provided as communication paths through which the plural first openings communicate with each other.
In this structure, it is possible to easily realize a tunnel structure only by designing the opening dimension or opening position of the first openings provided in the first intermediate plate and that of the second openings provided in the second intermediate plate.
Moreover, as the third openings (communication paths) through which the plural first openings communicate with each other (for example, one of the first openings and another one of the first openings) are provided in the third intermediate plate, even when evaporated bubbles pass continuously from one of the first openings through the communicating sections (communicating sections between the first openings and the second openings), a liquid refrigerant can enter the one of the first openings from the other one of the first openings via the communicating path. In this way, it is possible to prevent the liquid refrigerant from being exhausted within the first openings and a sufficient cooling performance can be maintained.
The ninth aspect of the apparatus of the present invention
The third openings provided in the third intermediate plate enable the communication between first openings within which a refrigerant is in a state of boiling and other first openings within which a refrigerant is not in a state of boiling, in the eighth aspect of the cooling apparatus boiling and condensing refrigerant.
In this case, as a liquid refrigerant is supplied to the one of the first openings from other first opening via the third opening (communication path) provided in the third intermediate plate, the liquid refrigerant can be prevented from being exhausted in the one of the first openings within which the refrigerant is in a state of boiling.
The tenth aspect of the apparatus of the present invention
A cooling apparatus boiling and condensing refrigerant comprises a refrigerant container forms a closed space, in which a refrigerant is stored, together with a plate to the surface of which a heat-generating member is attached; wherein a heat-generating member, from which the refrigerant stored in the refrigerant container receives heat and is evaporated into vapor, is cooled by releasing the latent heat of the refrigerant vapor to the outside; and wherein a tunnel structure is provided on the inner surface of the plate by press working.
In this case, cutting work that requires time and cost can be obviated and it is possible to easily form a tunnel structure (bag-shaped) by press working at a low cost.
The eleventh aspect of the apparatus of the present invention
The tunnel structure is composed of plural pillar portions that are perpendicular to the inner surface of the plate and cap portions formed by enlarging the tops of the pillar portions in the horizontal direction, in the tenth aspect of the cooling apparatus boiling and condensing refrigerant.
In this structure, cavity portions can be formed between neighboring pillar portions and a bag-shaped tunnel structure can be formed by covering the upper portions of the cavity portions by the cap portions.
The twelfth aspect of the method of the present invention
A method of forming the tunnel structure on the inner surface of the plate in the cooling apparatus boiling and condensing refrigerant in the eleventh aspect, comprises a first press process in which plural pillar portions are press-worked into pyramids or cones on the inner surface of the plate and a second press process in which the cap portions are formed by pressing down the tops of the pillar portions, which are pyramid-shaped or cone-shaped, to a fixed height and enlarging them in the horizontal direction.
With this manufacturing method, a tunnel structure (bag-shaped) can be formed easily in a brief time only by applying the press working twice to the inner surface of the plate.
Moreover, as the cap portions are formed by pressing down the tops of the pillar portions to the fixed height in the second press process, the height of the cap portions can be made low and it is possible, as a result, to design a refrigerant container the height of which is low.
The thirteenth aspect of the apparatus and method of the present invention
The refrigerant container has a multilayer structure in which plural plane plates are stacked upon the plate, in the cooling apparatus boiling and condensing refrigerant in any one of the tenth to the twelfth aspects.
In this structure, the volume (inner volume) of the refrigerant container can be altered easily according to the increase/decrease in heat load because the inner volume of the refrigerant container can be altered by increasing/decreasing the number of the plane plates.